acpi sleep: demote acpi_sleep_init() to a late_initcall.

- It depends on the rest of the subsys_initcalls in acpi to be done to get
  the sleep info from the firmware. 
- It doesn't need to be available any earlier...

drivers/acpi/sleep/main.c

@@ -273,4 +273,4 @@ static int __init acpi_sleep_init(void)
 	return_VALUE(0);
 }
 
-subsys_initcall(acpi_sleep_init);
+late_initcall(acpi_sleep_init);